“SWIM (Sander/Woz Integrated Machine) - IWM with significant additional capabilities for MFM disks. 100% back-compatible with the IWM (actually contains 2 complete controllers: an original IWM and the new MFM-capable Integrated Sander Machine, or ISM. A crossbar switch inside the chip determines which of the cores is connected to the inputs and outputs). Even in MFM and 1.44M modes, requires the CPU to do all the low-level timing-intensive work of disk I/O, just like the original Disk II.” [mess]